The present invention relates generally to surgical instruments, and more particularly to methods and apparatus for stabilizing or immobilizing tissue during surgery. The tissue stabilizers described herein are particularly useful for stabilizing the beating heart during coronary artery bypass graft surgery.
Certain surgical procedures require the surgeon to perform delicate operations on tissues within the body that are moving or otherwise unstable. The ability to stabilize or immobilize the surgical site provides greatly improved surgical accuracy and precision and reduces the time required to complete a particular procedure. A large and growing number of surgeons, for example, are routinely performing successful coronary artery bypass graft (CABG) surgery on the beating heart by temporarily stabilizing or immobilizing a localized area of the beating heart. Methods and apparatus for performing a CABG procedure on the beating heart are described in U.S. Pat. Nos. 5,894,843 and 5,727,569 to Benetti et al., the entirety of which is herein incorporated by reference.
In a typical CABG procedure, a blocked or restricted section of coronary artery, which normally supplies blood to some portion of the heart, is bypassed using a source vessel or a graft vessel to re-establish blood flow to the artery downstream of the blockage. This procedure requires the surgeon to create a fluid connection, or anastomosis, between the source or graft vessel and an arteriotomy or incision in the coronary artery. Forming an anastomosis between two vessels in this manner is a particularly delicate procedure requiring the precise placement of tiny sutures in the tissue surrounding the arteriotomy in the coronary artery and the source or graft vessel.
The rigors of creating a surgical anastomosis between a coronary artery and a graft or source vessel demands that the target site for the anastomosis be substantially motionless. To this end, a number of devices have been developed which are directed to stabilizing a target site on the beating heart for the purpose of completing a cardiac surgical procedure, such as completing an anastomosis. Representative devices useful for stabilizing a beating heart are described, for example, in U.S. Pat. Nos. 5,894,843; 5,727,569; 5,836,311; and 5,865,730.
As beating heart procedures have evolved, new challenges have arisen in the design and engineering of the stabilization devices. The heart is typically accessed by way of a surgical incision such as a sternotomy or thoracotomy. Often one or more of the blocked or restricted coronary arteries are located a good distance away from the access incision requiring the stabilization device to traverse a longer and more tortuous path and engage the surface of the heart at somewhat difficult angular relationships or orientations. Under the most severe conditions, devices which operate to provide a mechanical compression force to stabilize the beating heart encounter difficulty maintaining mechanical traction against the surface of the heart. Similarly, devices which utilize vacuum to engage the heart have a great deal of difficulty creating and maintaining an effective seal against the moving surface of the heart.
Even when the beating heart has been effectively stabilized, the target coronary artery may be obscured by layers of fat or other tissue and is very difficult for the surgeon to see. Moreover, the stabilization devices may distort the tissue surrounding the coronary artery or the coronary artery itself such that the arteriotomy is maintained in an unfavorable presentation for completion of the anastomosis. For example, the coronary artery in the area of the arteriotomy may become excessively flattened, compressed or stretched in a manner that impedes the placement of sutures around the perimeter of the arteriotomy.
In view of the foregoing, it would be desirable to have methods and devices for stabilizing the beating heart that are capable of maintaining atraumatic engagement with the surface of the beating heart over a wider range of conditions and orientations. It would be further desirable to have stabilization methods and devices which provide for favorable presentation of the coronary artery.
The present invention will be primarily described for use in stabilizing the beating heart during a surgical procedure, but the invention is not limited thereto, and may be used in other surgical procedures.
The present invention is a tissue stabilizer having one or more stabilizer feet that may be adjusted or oriented to provide optimal engagement against the tissue to be stabilized or to provide an optimal presentation of a portion of the stabilized tissue. The present invention may also include a tissue stabilizer having one or more flexible or compressible seals to ensure a reliable seal against the target tissue and may also include a stabilizer foot having at least one portion which is adjustable relative to the remainder of the stabilizer foot.
One aspect of the present invention involves a device for stabilizing tissue within a patient""s body comprising a base member, a first stabilizer foot extending outwardly from the base member and being rotatable relative to the base member about a first axis, and a second stabilizer foot extending outwardly from the base member and being rotatable relative to the base member about a second axis. Preferably, the first and second stabilizer feet are independently rotatable relative to the base member. In a preferred embodiment, the first axis and the second axis are substantially parallel.
The first and second stabilizer feet may each have hollow interiors defining first and second vacuum chambers each having at least one opening adapted to engage at least a portion of the tissue. The openings adapted to engage at least a portion of the tissue to be stabilized may have a raised seal around a perimeter thereof. In one variation the raised seal is made of a substantially rigid material. In other variations the raised seal is made of an elastomeric material or a compressible foam material.
The base member may comprise an interior chamber therein, the interior chamber of the base member being in fluid communication with the first and second vacuum chambers. The base member may comprise a front base portion and a rear base portion, the front base portion being sealingly affixed to the rear base portion. The device may also include a post having a distal end connected to the base member and a proximal end terminating in a ball-shaped member. A shaft may be provided having a socket at a distal end, the socket being operably engaged with the ball.
Another aspect of the present invention involves a device for stabilizing tissue within a patient""s body having a base member and at least one stabilizer foot extending outwardly from the base member in a first direction, the stabilizer foot being rotatable relative to the base member about an axis of rotation which is oriented in substantially the same direction as the first direction. Preferably, the axis of rotation is at an angle of no more than about 25xc2x0 to the first direction, more preferably, the axis of rotation is substantially parallel to the first direction.
In a preferred variation, the stabilizer foot has tissue engaging features adapted to engage an external surface of the tissue to be stabilized, the tissue engaging features being disposed at the bottom of the stabilizer foot. The tissue engaging features may comprise a vacuum chamber, preferably having a single opening for engaging the tissue to be stabilized, or may comprise a plurality of vacuum ports. The tissue engaging features may also comprise a textured surface, a perforated sheet, or a perforated sheet having projections extending outwardly therefrom. Preferably, the axis of rotation of the stabilizer foot is offset from the tissue engaging features, more preferably offset from and parallel to the tissue engaging features.
The stabilizer foot may have a hollow interior defining a vacuum chamber with a bottom opening adapted to engage at least a portion of the tissue. The stabilizer foot may also have a raised seal disposed around a perimeter of said opening, preferably around substantially the entire perimeter. The raised seal may be made from a rigid material, an elastomer, or a compressible foam. The vacuum chamber may have an inlet passage in fluid communication with a source of negative pressure. Preferably, the inlet passage is in fluid communication with an interior chamber within the base member. The base member may include an external fluid connection to supply negative pressure to the interior chamber of the base member.
Another aspect of the present invention involves a device for stabilizing a coronary artery on a patient""s heart comprising a base member and a stabilizer foot for engaging a portion of the patient""s heart. The base member has an interior chamber and at least a first bore, typically a cylindrical bore, having a first end in fluid communication with the interior chamber of the base member and a second end open to the exterior of the base member. The stabilizer foot has a substantially cylindrical fitting having a longitudinal axis, at least a portion of the fitting positioned within the bore and being rotatable within the bore about the longitudinal axis.
The stabilizer foot may have a hollow interior defining a vacuum chamber, the vacuum chamber having at least one chamber opening adapted to engage at least a portion of the heart. The fitting may further have a fluid passage having a first end in fluid communication with the interior chamber of the base member and a second end in fluid communication with the vacuum chamber of the stabilizer foot. A raised seal may be disposed substantially completely around the perimeter of the chamber opening. The raised seal may be rigid, compressible or flexible, preferably compressible or flexible. In a preferred embodiment, the raised seal has a durometer with a valve in the range of between about 35 Shore-A to about 100 Shore-A.
The stabilizer foot fitting may comprise a flange and further include an annular seal positioned adjacent the flange. Preferably, the annular seal is positioned between the flange and the base member. The annular seal is preferably an O-ring. The fitting includes at least one flexure having a free end and a raised portion extending radially from the free end. The raised portion preferably engages the first end of the first cylindrical bore to restrict movement of the fitting relative to the base member.
The tissue stabilizer may further include a second substantially cylindrical bore having a first end in fluid communication with the interior chamber of the base member and a second end open to the exterior of the base member. The tissue stabilizer may have a second stabilizer foot having a substantially cylindrical fitting having a longitudinal axis, at least a portion of the second stabilizer fitting positioned within the second bore and being rotatable within the second bore about the longitudinal axis of the fitting of the second stabilizer foot.
Another aspect of the present invention involves a stabilizer foot for use in engaging a portion of tissue within a patient""s body which includes a first foot portion having at least one vacuum port, a second foot portion having at least one vacuum port, and at least one malleable member connecting the first foot portion to the second foot portion, whereby the orientation of the first foot portion can be adjusted relative to the second foot portion. Preferably, the first foot portion is a substantially rigid unitary member having at least two vacuum ports.
The first foot portion may have a fluid passage in fluid communication with each of the vacuum ports associated with the first foot portion and the second foot portion may have a fluid passage in fluid communication with each of the vacuum ports associated with the second foot portion. The malleable member may be a cylindrical tube having a first end, a second end, and a lumen extending therebetween, the lumen fluidly connecting the fluid passage of the first foot portion with the fluid passage of the second foot portion, preferably, the tube is made of stainless steel. In another variation, a flexible tube may be provided to connect the fluid passage of the first foot portion to the fluid passage of the second foot portion. The malleable member is then preferably offset from the flexible tube. Preferably, the stabilizer foot includes two malleable members offset from opposing sides of the flexible tube.